Characterizing Thermal Runaway of Reservoir Rocks Under Electromagnetic Irradiation Towards Hydrogen Generation from Petroleum Reservoirs

Abstract

Abstract In-situ hydrogen generation and extraction directly from petroleum reservoirs provides a new solution to meet the increasing need for clean energy and to mitigate greenhouse gas emissions. This method leverages the abundant petroleum resources while simultaneously sequestrating carbon by-products underground. To enable in-situ clean hydrogen production from petroleum reservoirs, we proposed electromagnetic (EM)-assisted catalytic heating technology. Although significant potential has been recently assessed through lab-scale experiments and preliminary techno-economic analysis, the heating behaviors and interactions between EM waves and reservoir rocks are poorly understood, especially at a high enough temperature when hydrogen is generated. This study aims to elucidate the underlying mechanisms regarding the heating performance of sandstone and shale rocks under microwave irradiation. Advanced characterization techniques are employed to analyze the changes of rocks before and after microwave heating. The thermal runaway (TR) phenomenon is identified for the first time for San Saba sandstone rocks at 568°C and Mancos shale rocks at 253°C when they are exposed to microwave radiation. We further investigated the interactions of microwave with each pure mineral (e.g., albite, chlorite, illite, microcline, dolomite, kaolinite, calcite, and quartz) using a microwave reactor system. We identified that chlorite, albite, and illite are the main minerals that lead to the TR phenomenon. We also found that a high temperature can be easily achieved for both rocks at a much lower input power after TR, resulting in approximately 50% energy saved when the reservoir rocks are re-heated to 500°C. The occurrence of TR can therefore enhance the heating efficiency of reservoir rocks, reduce energy input, and significantly decrease the cost of in-situ hydrogen production from petroleum reservoirs using our proposed EM-assisted catalytic heating technology.